New technology has given us the ability to address corneal astigmatism and presbyopia with a toric multi-focal IOL. The best results with these IOLs require proper alignment of the toric axis for the astigmatism and then centration of the diffractive rings in the pupil for the multi-focality.
We want to center the diffractive rings of the IOL in the pupil while rotating the toric markers to the correct steep axis. To mark the toric axis on the cornea, I will align a Mendez gauge with the cardinal meridians and then use a cystotome to do light puncture marks in the anterior cornea at the desired axis. These marks are easily visible during IOL insertion and then it becomes easy to simply align the toric lens markings with these corneal markings. Next, keeping the toric marks aligned, the lens is centered in the visual axis by asking the patient to look at the microscope lights while I align the Purkinje images with the center of the IOL.
The result is excellent alignment and centration which allows us to give a highly accurate refractive result and deliver the best vision to our patients.
